With Twitter as his Excalibur, the president takes on his doubters, powered by long spells of cable news and a dozen Diet Cokes. But if Mr. Trump has yet to bend the presidency to his will, he is at least wrestling it to a draw.

The Media Relations Director works with the Vice President of Public Affairs and the Senior Director of Public Affairs to plan and execute communications initiatives including media outreach and tracking, message creation and distribution in a...